The legal team for Domain's former chief executive Antony Catalano argued the Fairfax board did not give its shareholders an opportunity to consider his competing offer at last week's annual general meeting, and that it should have been postponed.

It was also argued that Fairfax shareholders were being "short changed" by $600 million because the share price of Nine has "significantly" fallen since the deal was announced in July.

Since July, Nine's share price has fallen from its peak of $2.56 to $1.70 — down more than 32 per cent.

Mr Catalano, who owns a 1 per cent stake in Fairfax, sent a letter to the board the night before the AGM offering to buy up to 19.9 per cent of Fairfax shares, sell its non-core assets and be appointed to the Fairfax board.

Only Nine's deal was put to Fairfax shareholders and more than 80 per cent voted in favour of the takeover.

Fairfax chairman Nick Falloon told shareholders on the morning of the AGM that Mr Catalano's letter "contains no actual proposal that could be considered by Fairfax shareholders as an alternative" to Nine's offer.

Andrew Broadfoot QC, representing Mr Catalano, argued that when the deal was first announced, "Fairfax shareholders were contributing 45 per cent of the value of the merged entity, but receiving 49 per cent of the value".

But since the "significant erosion" of Nine's share price, Fairfax shareholders would "now be contributing 50 per cent, but receiving 49.9 per cent of the value".

"There was no good purpose in providing that [Mr Catalano's bid] to shareholders or delaying the shareholders meeting in order to address that," Justice Jacqueline Gleeson said.

This was particularly the case "in circumstances where the board had identified they had no intention of appointing him to the Fairfax board," she said.

What happens now the court has approved the merger?

Once the deal is completed in early December, the Fairfax brand name will cease to exist.

The new entity, which will simply be called "Nine", will own the free-to-air Nine Network, The Sydney Morning Herald, The Age, The Australian Financial Review, a majority stake in Domain, streaming service Stan and a 54.5 per cent stake in radio network Macquarie Media.

It will be led by Hugh Marks and Peter Costello, the chief executive and chairman of Nine Entertainment.

Nine shareholders are set to own 51.1 per cent of the combined company and Fairfax owners will have the remaining 48.9 per cent stake.

The Australian Competition and Consumer Commission approved Nine's takeover of Fairfax earlier in November.

Justice Gleeson said reasons for her decision will be published "in due course".

Mr Catalano's legal team said he may appeal the decision.

At 2:00pm (AEDT), Nine Entertainment's share price fell 0.3 per cent to $1.70, and Fairfax was flat at 63.5 cents.